A STUDY OF RHUS GLABRA 1 83 



somewhat glaucescent green above, very glaucous beneath ; 

 leaflets 13-17, small, sessile, drooping on the rachis rather than 

 spreading away from it on the same plane, oblong-lanceolate, 

 5-6 cm. long, slenderly acuminate and somewhat irregularly 

 and coarsely serrate-toothed below the acumination, as well as 

 more lightly and evenly serrate in the middle : panicle pyram- 

 idal, small, about 8 cm. long, slender-peduncled, somewhat 

 recurved or drooping. 



Known only from Yellow River, near McGuire's Mill, 

 Guinnett County, Georgia, July 11, 1893, John K. Small; 

 type in National Museum, sheet No. 19816. A small and 

 very graceful species, recalling some of the far-southwestern 

 forms found in Arizona. 



10. RHUS LUDOVICIANA, sp. nov. 



Shrub with quite slender branches, the foliage not large 

 ascending, glabrous except as to the hairy line of the rachis, 

 about 2.5 dm. long; leaflets 11-15, opposite, of thin texture 

 even in full maturity, dull green above, moderately glaucous 

 beneath, 5-8 cm. long, attenuate, acute rather than acuminate, 

 evenly serrate, the serratures 12-16 on each margin: panicle 

 small, pyramidal, 8 cm. long, 4 cm. broad toward the base ; 

 drupelets obliquely orbicular, of a dark red-purple and not 

 strongly pubescent. 



The type specimen is in my own herbarium, from along the 

 seaboard in southwestern Louisiana, at Cotes Blanches, October 

 10, 1884, by A. B. Langlois. A strongly-marked, probably 

 small species, said to form low thickets in a peculiar maritime 

 region that is still almost unknown botanically. 



If the Rhus angustifolia Bauhin, believed to have come from 

 the coast of Brazil, was derived from some North American 

 coast by that voyager of nearly or quite three centuries ago, it 

 would be easy to fancy that the specimen in Burser's herba- 

 rium, which became Bauhin's type, was from some shore of the 

 Gulf of Mexico, and even may have been identical with what is 

 here described as R. ludoviciana, and which is the only known 

 maritime ally of R. glabra. And that which may elevate this 



Proc. Wash. Acad. Sci., February, 1907. 



